package com.ccsc.auth.utils;

import com.ccsc.auth.global.SvcConstants;
import javax.crypto.*;
import javax.crypto.spec.SecretKeySpec;
import java.security.SecureRandom;

public class EncryptUtil {
    private static String Key = MD5.MD5Encode("CETCMasking");

    /**
     * 加密
     *
     * @param content  需要加密的内容
     * @param password 加密密码
     * @return
     */
    private static byte[] encrypt(String content, String password) {
        try {
            SecretKey secretKey = getKey(password);
            byte[] enCodeFormat = secretKey.getEncoded();
            SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");
            Cipher cipher = Cipher.getInstance("AES");// 创建密码器
            byte[] byteContent = content.getBytes(SvcConstants.DEFAULT_ENCODING);
            cipher.init(Cipher.ENCRYPT_MODE, key);// 初始化
            byte[] result = cipher.doFinal(byteContent);
            return result; // 加密
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 解密
     *
     * @param content  待解密内容
     * @param password 解密密钥
     * @return
     */
    private static byte[] decrypt(byte[] content, String password) {
        try {
            SecretKey secretKey = getKey(password);
            byte[] enCodeFormat = secretKey.getEncoded();
            SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");
            Cipher cipher = Cipher.getInstance("AES");// 创建密码器
            cipher.init(Cipher.DECRYPT_MODE, key);// 初始化
            byte[] result = cipher.doFinal(content);
            return result; // 加密
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 将二进制转换成16进制
     *
     * @param buf
     * @return
     */
    private static String parseByte2HexStr(byte buf[]) {
        StringBuffer sb = new StringBuffer();

        for (int i = 0; i < buf.length; i++) {
            String hex = Integer.toHexString(buf[i] & 0xFF);
            if (hex.length() == 1) {
                hex = '0' + hex;
            }
            sb.append(hex.toUpperCase());
        }
        return sb.toString();
    }

    /**
     * 将16进制转换为二进制
     *
     * @param hexStr
     * @return
     */
    private static byte[] parseHexStr2Byte(String hexStr) {
        if (hexStr.length() < 1)
            return null;
        byte[] result = new byte[hexStr.length() / 2];
        for (int i = 0; i < hexStr.length() / 2; i++) {
            int high = Integer.parseInt(hexStr.substring(i * 2, i * 2 + 1), 16);
            int low = Integer.parseInt(hexStr.substring(i * 2 + 1, i * 2 + 2), 16);
            result[i] = (byte) (high * 16 + low);
        }
        return result;
    }

    public static String encrypt(String data) {
        byte[] encryptResult = encrypt(data, Key);
        String encryptResultStr = parseByte2HexStr(encryptResult);
        return encryptResultStr;
    }

    public static String decrypt(String data) {
        byte[] decryptFrom = parseHexStr2Byte(data);
        byte[] decryptResult = decrypt(decryptFrom, Key);
        String decryptResultStr = new String(decryptResult);
        return decryptResultStr;
    }

    private static SecretKey getKey(String strKey) {
        try {
            KeyGenerator keyGenerator = KeyGenerator.getInstance("AES");
            SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG");
            secureRandom.setSeed(strKey.getBytes(SvcConstants.DEFAULT_ENCODING));
            keyGenerator.init(128 ,secureRandom);
            return  keyGenerator.generateKey();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    public static void main(String[] args) {
        String content = "dmdba123";
        //加密
        System.out.println("加密前：" + content);
        System.out.println("加密后：" + encrypt(content));
        //解密
        System.out.println("解密后：" + decrypt(encrypt(content)));
    }
}
